# US 11,078,627 B2 · High tensile strength paper suitable for use in electrochemical cells

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- Number: US 11,078,627 B2
- Document ID: US11078627B2
- Status: Granted
- Kind: B2
- Application number: 16/526,135
- Filed: 2019-07-30
- Published: 2020-02-20
- Granted: 2021-08-03
- Earliest claimed: 2018-08-14
- Assignees: Dupont Safety & Construction, Inc.
- Applicants: Dupont Safety & Construction, Inc.
- Inventors: Mehdi Afshari; Byoung Sam Kang
- Web page: https://patentgrep.com/patent/US11078627B2

## CPC

- D21H 13/26: Polyamides; Polyimides
- D21H 13/12: from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- H01M 8/0239: Organic resins; Organic polymers
- H01M 50/414: Synthetic resins, e.g. thermoplastics or thermosetting resins
- H01M 50/44: Fibrous material
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M 50/491: Porosity
- H01M 50/494: Tensile strength
- Y02E 60/10: Energy storage using batteries
- Y02E 60/50: Fuel cells
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A paper suitable for use as a separator paper in electrochemical cells and an electrochemical cell comprising same, the paper comprising as the sole fibrous components 95 to 100 weight percent fibrils and 0 to 5 weight percent aramid fibrids and having a thickness of 10 to 40 micrometers and a tensile strength of at least 15 megapascals or greater, the fibrils comprising a polymer blend of 80 to 96 weight percent polyparaphenylene terephthalamide and 4 to 20 weight percent of polyvinylpyrrolidone; the fibrils having a diameter of 10 to 2000 nanometers, a length of 0.2 to 3 millimeters, a surface area of 3 to 40 square meters/gram, and a Canadian Standard Freeness of 0 to 10 milliliters.

## Claims

### Claim 1

A paper suitable for use as a separator paper in electrochemical cells comprising, as the sole fibrous components:
a) 95 to 100 weight percent fibrils, and
b) 0 to 5 weight percent aramid fibrids;
the paper having a thickness of 10 to 40 micrometers and a tensile strength of at least 15 megapascals or greater,
wherein the fibrils comprise a polymer blend of 80 to 96 weight percent polyparaphenylene terephthalamide and 4 to 20 weight percent of polyvinylpyrrolidone,
the fibrils having
i) diameter of 10 to 2000 nanometers,
ii) a length of 0.2 to 3 millimeters,
iii) a specific surface area of 3 to 40 square meters/gram, and
iv) a Canadian Standard Freeness of 0 to 10 milliliters.

### Claim 2 (depends on 1)

The paper of claim 1 having a tensile strength of 100 megapascals or less.

### Claim 3 (depends on 2)

The paper of claim 2 having a tensile strength of 50 megapascals or less.

### Claim 4 (depends on 1)

The paper of claim 1 having a mean flow pore size of 0.05 to 0.5 micrometers.

### Claim 5 (depends on 1)

The paper of claim 1, wherein the fibrils have a diameter of 10 to 1200 nanometers.

### Claim 6 (depends on 1)

An electrochemical cell comprising the paper of claim 1.